I want to connect a CentOS 6.4 Linux Box with two NICs to a Cisco 2960S using LACP 802.3ad port aggregation. This mainly for redundancy reasons (and hopefully more bandwith). We don't use VLAN tagging.

With the config listed below the link aggregation only works partially. Approx half of the network hosts can ping and ssh the Linux box, whereas the other half cannot. Same is true for the Linux box itself, approx only half of the hosts can be pinged.

Setting up adapter bonding (or in Cisco speech EtherChannel) shouldn't be that hard. But does anyone know what's wrong here?

2 Answers
2

I wonder if this is because you are setting Fast LACPDUs (lacp_rate=1) on the Linux end of the bond, but the switch is still running in the default Slow LACPDUs mode (the default), so the bond isn't negotiating properly.

If this is right, you'll be able to either show etherchannel 2 detail or show lacp internal on the switch, the flags on the Channel Group will probably say SA (Slow Active). If you do a show lacp neigh you'll probably see F on the Linux end (Fast).

To resolve this, just remove lacp_rate=1 from your BONDING_OPTS and restart.

Everything else is configured correctly, though you don't need alias bond0 bonding, the network scripts will load and configure the bonding driver when starting the interface.

That was indeed a configuration error. But the problem still persists after this correction.
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StackUnderflowJul 1 '13 at 14:48

Why not change to fast LACPDUs on the switch?
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185140777Mar 2 at 15:08

all depends on the switch. I have mine set to fast on the switch side. the bond came up even with my linux box not taking the lacp rate command due to module options being ignored.
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KendrickMar 23 at 15:29

You can also just add NM_CONTROLLED=no to any ifcfg-files for interfaces you don't want managed by NM. I do this on my laptop, so network scripts manage the bridge and wired connection, but I can still use wifi from the graphical interface.
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jamiebJan 9 '14 at 10:10

In fact you should do this, because starting NM in the graphical interface with nm-applet will let NM manage any interfaces which don't have NM_CONTROLLED=no anyway.
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jamiebJan 9 '14 at 10:11

I have seen where nm option doesnt work right so its good to have the info for both. This fixed an issue on my box where bond0 was created but none of the slaves would attach to the bond interface. also a side note bond.cfg modprobe didn't put the options on the bond if I had to specify all options in the bonding_opts for it to take.
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KendrickMar 23 at 15:27